Lithographic processes, such as photolithography, are commonly utilized during semiconductor processing. Lithographic processes have minimum capable feature sizes, F, which are the smallest feature sizes that can be reasonably formed with the processes. For instance, photolithography may be limited by factors such as optics and radiation wavelength.
A continuing goal in semiconductor processing is to reduce the size of individual electronic components, and to thereby enable smaller and denser integrated circuitry. A concept commonly referred to as “pitch” can be used to quantify the density of an integrated circuit pattern. Pitch may be defined as the distance between an identical point in two neighboring features of a repeating pattern. Feature size limitations of a lithographic technique can set a minimum pitch that can be obtained from the lithographic technique.
Pitch multiplication, such as pitch-doubling, is a proposed method for extending the capabilities of lithographic techniques beyond their minimum pitches. Pitch multiplication may involve forming sublithographic features (i.e., features narrower than minimum lithographic resolution) by depositing a material to have a thickness which is less than that of the minimum capable lithographic feature size, F. The material may be anisotropically etched to form the sublithographic features. The sublithographic features may then be used for integrated circuit fabrication to create higher density circuit patterns than can be achieved with conventional lithographic processing.
Difficulties may be encountered in processing associated with formation and utilization of sublithographic features. For instance, some processing may utilize traditional photolithography for fabricating masks utilized during chopping and/or other modification of sub-photolithographic features. It can be difficult to align and utilize a photolithographic-scale structure during modification of a sub-photolithographic-scale structure.
It would be desirable to develop new methods for forming and utilizing sublithographic features. It would also be desirable to develop new structures utilizing such new methods.